Dusting powder



' April 2, 1940. P. A. RAICHE 2,195,424

DUSTING POWDER Filed Ju1y24, 1935 3 Sheets-Sheet 1 April 2, 1940. P,RA|HE 2,195,424

DUSTING POWDER Filed July 24, 1935 3 Sheets-Sheet 2 /%/ZHW "VI 7 April2, 1940. P, CHE r 2,195,424

nusrme POWDER Filed July 24, 19:55 s sneets-sheet s Ifiverz for W 0 h fize Patented Apr. 2, 1940 UNITED. STATES PATENT OFFICE nUs'rrNe POWDER 3Paul A. Raiche, North Providence, R. I.' Applicationv July 24, 1935,Serial No. 32,963v

t 2 Claims. (01. 18-47) My present invention relates to the rubber art,

' and has particular reference to the manufacture of nipples and otherrubber articles. The manufacture of nipples has involved a plurality ofoperations, including many hand operations. The sheets of rubber haveheretofore been blanked in multiple, to provide two sections which havebeen cemented at the edges, then opened at the end, then seamed,inspected, cemented at the open end, curledat the open end to form aroll, mounted on curing forms, cured, and finally,

stripped'from the forms.

It is the principal object of my invention to simplify the manufactureofnipples and similar articles by reducing the operations required,without sacrifice of quality in the resulting product. To this end, Ihave devised a method and an apparatus for forming a nipple blank whichcan be cured, thus eliminating the greater part of the operations nowfound necessary. I have also provided means for smoothing the nipplesurface, to eliminate all manufacturing marks, roughnesses, orblemishes.. 1

With the above and other objectsand advantag eous features in view, myinvention consistsof a novel method anda novel arrangement of parts,

more fully disclosed in the detailed description following, inconjunction with the accompanying drawings, and more specificallydefined in the claims appended thereto.

In the drawings, c Fig. 1 is a top plan view of one construction offorming dies;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-'3 of Fig. 1;

v Fig. 4 is a bottom plan view of the upper die;

Fig. 5 is a top plan view of the lower die;

Fig. 6 is an enlargeddetail of a modified land arrangement Fig. '7 is aperspective view of and one. type of sheet blank;

Figs. 8 and 9 are similar views, illustrating different sheet blanksutilizable' therewith;

Fig. 10 is a sectional detail of a die construction showing the moldingof a sheet blank;

Fig; 11 is a side elevation showing the resulting molded nipple on theformer;

a novel former Fig. 12 is a view, similar to Fig. 9, but illustratfaceof the die is formed with a rib 3 bevelled at 4 and 5 on its outer andinner faces respectively and having a fiat and relative narrow land 6.

The upper or pressure applying die i has a stem or shank 8 forsecurement in the reciprocating head of any well known form of pressandpreferably has air openings 9. The die I also has a rib Hi the innerand outer faces II and I2 of which are bevelled in a mannercorresponding to the bevelling of the bed or lower die.

The bevelling of the sides of the rib ID leave. a narrow land IZ-a whichlatter registers with the land 6 of rib. 3 of the lower bed die and isof slightly less width than the latter.

In operation, two uncured rubber sheets S, which may betrimmedpreviously or subsequent to connection are placed on the. lower,or bed die in the position illustrated: in Figures 2 and. 3 of thedrawings. The upper, or pressure applying die is then lowered andbrought into forcible contact with the uppermost of the two rubbersheets,

' causing pressure to be applied to the two sheets rubber sheets arethus easily and quickly united along relatively narrow lines, thepressure of the dies on the rubbersheets being confined to the narrowlines defined by the lands 6 and lZa. The dies are hot, the temperaturedepending on the grade of stock, and ranging from' 105 F. to 290 F.; themore plastic the stock, the lower the temperature. The pressure is greatenough to substantially squeeze out the rubber between the lands, thusleaving a very small bead, and for a four die press should be in theneighborhood of four tons.

As there are no ribs on the large end l3 of the dies, this end of thenipple will be left open, that is, the dies will not act to unite thetwo sheets of rubber at this point.

The'upper die may be operated as many times as may be required, due tothe thickness of the rubber sheets in order to effect the desired. unionofthe parts. v

' It is particularlyto be noted that due to the bevelling of the ribs ofthe dies, the points of contact with the material occur but over a verysmall the two sheets; any surplus is trimmed off due to the sharp upperdie.

The above described pressure unions produce nipple blanks that may becured without further manufacturing operation; the amount of the stock,its quality, and the temperature of curing mustfbe very carefullygaugedto prevent the formation of a perceptible join bead.

Although the above described manufacture is satisfactory, I have foundit feasible to provide an alternative manufacture which ensures aperfeet product, having uniform cross-section at any point along itslength. I have therefore provided two dies, an upper die I l and a lowerdie iii, and a cooperating former l6, which as lus'trated in Figs. '7 to10 includes a nipple form it, a recess l8, and a shank it, the shankbeing bored to receive the usual pin of a curing frame. I use a blanksuch as rubber sheet 29, see Fig. '7, which has one end 2! turned overto form a thickened edge, or I may. use a rubber tube 22, see Fig. 8, ora rubber cap 23, see 9, each preferably having a thickened edge asshown. The former and the blank is inserted in the lower die, and theupper die is pressed into engagement, as indicated in Fig. 10, wherebythe blank is shaped into a nipple blank and the surplus is trimmed off.The blank is of suffilcient thicknose to exactly fill the space betweenthe former and the die. The pressure on the blank be tween the formerand the dies produces a rubber flow which completely fills the availablespace. and produces a nipple blank having a rubber section of uniformthickness at any point of its length. The dies are preferably heated atfrom 105? F. to 299 F.; moreover, as many dies may be provided,preferably inparallel relation, as can conveniently handled by theworkmen.

The resulting. nipple blank may have a slight bead or edge 24, see Fig.12, at the region of the die lands, although the rubber content of theblank. be gauged to exactly fill the available space. The nipple blankand former are then turned a quarter turn, and pressed between a secondset of shaping dies, 25, 26, see Fig. 13, these. being ground to presenta smooth area adje'tcent the bead location. This second shapingdistributes excess material so as to eliminate any or edges, and tofillany grooves or regions of reduced or enlarged cross-section, wherebythe resulting shaped nipple blank is perfectly formed, and is ready forcuring.

A'further forming is possible during the curing operation, wherebynipples made in accordance with the first described manufacture, and

also with the second described manufacture, may be smoothed. This isaccomplished by using a dusting powder which contains a flux oringredient capable of producing an initial running or flow of therubber, and an accelerator, or second ingredient for producing a veryslightly'delayed,

but quick, set of the rubber, whereby all surface inequalities aresmoothed out. The. preferred ingredients for obtaining these results arezinc stearate for the flux, and an accelerator of standard type, whichare used in the form of a composite comminuted dusting powder, asuitable proportion being half and half. The curing temperature is inthe neighborhood of 290 F., and at about 85 lbs. pressure; the nippleshrinks slightly during the curing, so as to set in the.

exact shape of the former, thus ensuring uniformity of the finishedproducts, as the forms are all exact duplicates. I

While I have. described specific arrangements for producing the desired.formation of nipple blanks, the arrangements may be extended to otherarticles for which smooth exteriors are required, and may includeplastic materials other than rubber, but of a similar nature. Desiredchanges in the shape of the dies, in the structrue of the diesand thenumber used, in the sheet blanks used, and in the ingredients utilizedfor the final smoothing during. the. curing operation,

may be made to suit different article require- .ments, within the spiritand the scope of the said initial running.

said rubber surface'immediately subsequent to.

PAUL A. RAICHE'.

